Starting mechanism for an internal combustion engine



Aug. 30, 1960 F. DE MILLAR v S'IARTING MECZl-LM \T ISM FOR AN INTERNALCOMBUSTION ENGINE Filed May 12, 1958 3 Sheets-Sheet 1 aibz" z aza, az ZiM wk/way:

30, 1960 F. 0. DE MILLAR 2,950,780

STARTING MECHANISM FOR AN INTERNAL COMBUSTION ENGINE Fi led May 12, 19583 Sheets-Sheet 2 Aug. 30, .1960

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dafirzzeyf United States Patent STARTING MECHANISM FOR AN INTERNALCOMBUSTION ENGINE Floyd 0. De Millar, Fr'amingham, Mass, assignmtoCorporation, Framingham Center, Mass, a corporation of MassachusettsFiled May 12, 1958, Ser- No. 734,473

8 Claims. (Cl. 185-41) The present invention relates to a turning devicefor imparting a rapidly accelerating movement to a rotatable body andmore particularly to improvements in manually operated spring startingmechanisms of the type disclosed and claimed in my United States PatentNo. 2,804,173, issued August 27, 1957.

For a long time there has been a need for a small inexpensive manuallyoperated starter to replace the conventional pull-rope starter onoutboard engines and engines of the type employed on lawnmower-s. Thetroubles attendant to the conventional rope starter are well known andrequire no elaboration here. Electric starters have been developed whichare highly satisfactoi'y from the standpoint of performance. However,for the most part, electric starters have supplanted rope starters onlyon outboard engines of 15 horsepower and higher. The cost of electricstarters prohibits their use on engines of smaller horsepower,particularly those engines of less than 7.5 horsepower.

Accordingly, the object of this invention is to provide a starter forgasoline engines which is easier to operate than the conventional ropestarter, is cheaper to manufacture than an electric starter, provides ahigh starting torque, is durable, will operate satisfactorily under alltypes of climatic conditions, and is adaptable with engines of varioussizes.

Another object of this invention is to provide a spring starter whichconstitutes an improvement over the starter disclosed and claimed insaid issued Patent No. 2,804,- 173. The most significant improvementeifected by the present invention is the reduction in complexity of con-'struction.

I A more specific object of this invention is to provide a springstarter for imparting a rapidly accelerating rotative movement to arotatable body comprising, a fixed housing provided with an end wall, ashaft rotatably mounted in said housing, one end of said shaft extendingthrough said end wall, a crank arm outside of said housing, meanssecuring said crank arm to said shaft, a pawl within said housingoperatively coupled to said shaft for rotation therewith, a drumrotatably mounted on said shaft, said drum having a plurality ofcircumferentially arranged gear teeth positioned to be drivingly engagedby said pawl when said shaft is rotated by said crank 'arm in a firstdirection, said drum also having a notch cut in its surface in axialspaced relation with said'gear teeth, a spiral spring Within saidhousing, said spring having an outer end secured to said housing and aninner end provided with a hook normally engaging said drum in positionto fall into and engage said notch as said drum is rotated in said firstdirection by said pawl, whereby to cause winding of said spring uponsaid drum as said drum rotates in said first direction, selectivelyoperated means for disengaging said pawl from said gear teeth to releasethe energy stored in said spring, whereby to rotate said drum in asecond opposite direction, and ihea'ns for connecting said drum to saidrotatable body Patented Aug. 30, 1960 ice - internal combustion engine;

Fig. 2 is a plan sectional view taken along line 22 of Fig. 1;

Fig. 3 is a fragmentary view similar to Fig. 2 showing how the starteris released by operation of the winding crank;

Fig. 4 is a bottom view partly in section of the same starter;

Fig. 5 is a vertical section taken through the center of the starter;

Fig. 6 is a plan view of the overrunning clutch which couples thestarter to the shaft of the internal combustion engine;

Fig. 7 is a vertical section through the center of the overrunningclutch;

' Fig. 8 is a sectional view of the same clutch taken along line 88 ofFig. 7; and,

Fig. 9 is a side elevational new of the winding drum of the starter.

Referring now to Figs. 1 and 5, numeral 2 designates the shaft memberwhich is to be driven. For purpose of illustration shaft 2 may beconsidered to be the main driving shaft of an outboard motor. However,it is to be understood that shaft 2 may also be the driving shaft of asmall internal combustion engine of the type employed on lawnmowers orsmall snow-throwers. The numeral 4 designates a portion of the top wallof the housing of the motor.

The spring starter comprises a cylindrical casing 6 hav ing a top endwall 8. The bottom end of the casing is open. Welded to the casing is aplurality of legs 10 of T-shaped cross section. These legs extenddownwardly and outwardly from the casing and are welded at their bottomends to a flat ring 12 which is concentric with casing a. Ring 12 has aplurality of spaced openings 14 to receive bolts '15 which together withnuts 16 are used to fixedly secure the casing to the top wall 4 of theengine housing. As most small internal combustion engines have securedto their drive shafts blades for promoting air circulation around theirouter casings the supporting members '10 of my starter unit, as shown inFig. 5, are designed to hold it an appropriate distance away from anysuch air cooling means.

' Top wall 8 of casing 6 is provided with a central opening 17. Formedintegral with top wall 8 and depending therefrom in axial relation'withopening 17 is a bearing sleeve 18. It is to be noted that sleeve 18 canbe formed independently of top wall 8 but secured thereto by suitablemeans, such as welding, instead of being formed integral with the topwall as shown.

Rotatably positioned within bearing sleeve 18 is a winding shaft 20; Thetop end of winding shaft 20 protrudes above the top wall 8 of casing 6and affixed thereto is a collapsible handle 22. Handle 22 is formed intwo parts with the two parts hinged together as at 24. Winding shaft 20extends down beyond the bottom end of bearing sleeve 18 and terminatesin an end section of reduced diameter that forms a shoulder 26 and isthreaded as at 28. A short distance above shoulder 26 winding shaft 20is provided with a diametrically extending opening adapted to receive alocking pin 30. Rotatably sun rounding sleeve 18 is a second sleeve 32.The latter has an internal flange 34 at its bottom end which engages'winding shaft 20 and is locked thereto by locking pin nection with themeans for releasing the energy stored in the spring of the starter.

Mounted on sleeve 32 is a cylindrical winding drum 42. The latter has aninternal annular flange 44 through which extends the threaded end ofwinding shaft 20. A nut 46 screwed into threads 28 keeps flange 44 insliding engagement with shoulder 26 of winding shaft 20. Drum 42 isprovided with a saw tooth notch 48 which is so located as to engage thehooked inner end 50 of a flat coiled power spring member 52 which isdisposed within casing 6. The casing has a slot 54 in its side wall toaccommodate the hooked outer end 56 of power spring member 52. Whenwinding drum 42 is rotated counterclockwise (Fig. 2) it acts on thehooked spring end 50 to wind up the spring member 52. The energy storedin spring member 52 when it has been wound upon winding drum '42 is-theenergy that is used to drive shaft 2 to start the engine to which thestarter is attached. The mechanism for rotating drum 42 to wind up thespring and the mechanism for holding the spring in wound condition andfor selectively releasing the spring are described hereinafter. Thesemechanisms are all operated by the handle 22.

Looking now to Figs. 2, 4, and 9 in particular, the winding drum 42 isprovided at its upper end with a ratchet gear 60. Gear 60 maybe formedintegral with drum 42 as shown or may be a separate element that issecured to the drum by suitable means, e.g., by welding. 'Mounted onsleeve 32 is a collar 62 provided with a peripheral flange 64 having anenlarged generally radial projection 66. Flange 64 engages flange 38 ofsleeve 32 and is in turn engaged by gear 60. The top surface ofprojection 66 is provided with two spaced ribs or stops 68 and 70. Thespace between ribs 68 and 70 is occupied by a flat locking member 72which is pivotally secured to the end of projection 66 by means of apivot pin 74. The opposite end of locking member 72 is notched as at 76to accommodate radial projection 49 of sleeve 32. Projection 40 andnotch 76 are so shaped as to permit them to pivot relative to eachother. Secured to pivot pin 74 on the under side of projection 66 is apawl 78. The connection between projection 40 and notch 76 permitspivoting of pawl 78 inwardly or outwardly, depending upon the directionin which radial.

projection 40 is rotated by handle 22 acting through shaft 20 and sleeve32; When locking member 72 is pivoted by projection 40 into. engagementwith stop 68, pawl 78 is in engagement with the teeth of ratchet gear 60(Fig. 2). This is accomplished when handle 22 is rotated in acounterclockwise direction as viewed in Fig. 2. When locking member 72is pivoted into engagement with stop 70, pawl 78 is disengaged from gear60. This is accomplished by moving handle 22 in a clockwise direction asviewed in Fig. 2. Thus winding drum 42 can be rotated by the handle 22only in one direction, the direction in which the spring is wound upondrum 42. When the handle is turned in the opposite direction, the energystored in spring 52 causes the drum to spin in a clockwise direction torelease the energy and permit the spring to return to its originalposition. When the drum is connected to the shaft 2 of the engine to beReferring to Figs. 2, 3 and 5, projection 66 has a slot 80 cut betweenits bottom surface andth-e top surface. of stop 70. Pivotally secured inslot 80 by means of a pivot pin 82 is an arm 84. The outer extremity ofarm 84 is provided with a flange 8'6. Attached to flange 86 is a flatstrip 88 of spring steel which is provided on its outer surface with abrake lining .90. As viewed in Fig. 2, the spring steel "strip 88extends in a clockwise direction away from arm 84. The brake lining 90bears against the inner wall of easing 6 which restrains spring strip 88against unwinding. The free end 92 of the spring strip 88 terminatesshort of projection 66.

, The'brake consisting of strip 88 and lining 90 slides readily relativeto housing 6 when the drum 42 is rotated counterclockwise (Fig.2) byoperation of handle 22. This is due to the fact that the brake issubjected to a pulling action by projection 66. However, when the handle22 is no longer being rotated in a direction to wind up spring 52, thebrake will not move in the opposite direction. The reason for this isthat projection 66 tends to exert a pushing force on the brake and thispushing force, aided by the fact that arm 84 can pivot relative toprojection 66, urges the brake into tighter engagement with the casing,causing it, and in turn the drum 42, to resist clockwise movement byspring 52.

The drum 42 is connected to the shaft 2 of the engine by means of anoverrunning clutch designated generally by the number 96. Clutch 96comprises a cylindrical clutch member 98 provided at its bottom end witha pair of internal keyways 100. These keyways are provided to receivekeys 102 aifixed to the upper end of engine shaft 2. At its upper endclutch'member 92 has three in- V ternal annular shoulders 104, 106, and108. The clutch started, the high torque applied to the drum by thespring 7 when gear 60 is released from pawl 78 will cause the member 98fits over the bottom end of drum 42 which is spaced from shoulder 104 byan approximate clearance to permit free rotation. Shoulder 106 isprovided with three equiangularly located tapped openings 110 whichreceive screws L12. Shoulder 108 supports an annular ring 114 whoseinner edge slidably engages drum 42. Screws 112 extend through suitableopenings in ring 114 and each screw carries a pawl 1 16 and a washer118. Small springs urge pawls 1'16 inwardly of the clutch member 98. Theends of these pawls engage ratchet teeth 122 formed in the bottom end ofdrum 42. The teeth 122 are oriented so that they act throughpawls 116 torotate clutch member 98 when the drum. is rotated clockwise by spring 52as viewed in Figs 2 and 3. Since clutch member 98 is keyed to engageshaft 2, it drives the shaft when the energy stored in spring 52 isreleased to drive drum 42. However, because of the shape of the ends ofpawls'116 and centrifugal force, once the engine is started the clutchmember 98 overruns the drum 42, thereby preventing injury to the spring52 or the other elements of the starter. Looking from the top toward thebottom of the starter, operation of the starter is as follows: Handle 22is swung to extended position and then turned in a counterclockwisedirection. Initial rotation of the handle cams pawl 78 from the positionof Fig. 3 to the position of Fig. 2. Continued rotation of the handlecauses pawl 78 to turn ratchet gear 60' and drum 42 in acounterclockwise direction to wind up spring 52. Because of theorientation of ratchet teeth 122, drum 42 will rotate relative to clutchmember 98. The brake consisting of steel strip 88 and lining 90 preventsdrum 42, handle 22 and the elements connecting them from rotatingclockwise. When spring 52 has been wound upon drum 42 sufliciently,handle 22 is rotated in the opposite (clockwise direction). This camspawl 78 back to'the position of Fig. 3, releasing ratchet gear '60 anddrum 42. As soonas this occus the energy stored in spring 52 causes drum42 to rotate clockwise. This in turn causes clutch 96 to drive shaft 2to start the engine.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. Therefore, it is to beunderstood that the inassayed vention is not limited in its applicationto the details of construction and arrangement of parts specificallydescribed or illustrated, and that within the scope of the appendedclaims it may be practised otherwise than as specifically described orillustrated.

I claim:

1. In combination with an internal combustion engine provided with arotatable shaft by means of which said engine may be started, a manuallyoperable spring starter, said starter comprising a fixed casing, a flatspring coiled upon itself within said casing, the outer end of saidspring attached to said casing, a winding drum for said spring rotatablysupported within said casing, means on said winding drum for acting onthe inner end of said spring to wind said spring upon said drum as saiddrum is rotated in a first direction, a handle, releasable meansconnecting said handle and said winding drum operative when said handleis rotated in said first direction to rotate said drum to wind saidspring thereon and operative when said handle is turned in a secondopposite direction to disconnect said drum from said handle whereby theenergy stored in said spring will cause said drum to spin in a saidsecond direction to unwind said spring, means for preventing rotation ofsaid drum in said second direction so long as said connecting meansremains in unreleased position, and means connected between said shaftand said drum for rotating said shaft in said second direction under theinfluence of said energy stored in said spring when said connectingmeans is released by movement of said handle in said second direction.

2. Apparatus for imparting a rapidly accelerating rotative movement to ashaft comprising, a fixed casing, a flat coiled spring positioned withinsaid casing with the outer end of said spring attached to said casingand the inner end of said spring having a hook, a winding drum rotatablysupported within said casing, said winding drum having means forengaging said hook and for winding said spring upon said drum as saiddrum is rotated in a first direction, a handle rotatably supported bysaid casing, releasable means connecting said handle and said windingdrum operative when said handle is rotated in said first direction torotate said drum in said same direction to effect winding of said springon said drum and operative when said handle is rotated in the oppositedirection to disconnect said dr-um from said handle whereby the energystored in the spring wound upon said drum will cause said drum to spinin said second direction to unwind said spring, means for preventingspinning of said drum in said second direction so long as saidconnecting means remains in unreleased condition, and means carried bysaid drum for driving said shaft when said drum rotates in said seconddirection.

3. A manually operable spring starter for imparting a rapidlyaccelerating rotative movement to a shaft comprising, a casing, a fiatspring coiled within said casing, the outer end of said spring beingattached to said casing and the inner end of said spring having a hook,a winding drum rotatably supported in said casing, said drum havingmeans engageable with said hook to wind said spring upon said drum whensaid drum is rotated in a first direction, a ratchet gear carried bysaid drum, a shaft rotatably supported within said casing in coaxialrelation with said drum, a handle secured to said shaft outside of saidcasing, a collar rotatably mounted on said shaft, said collar having afirst radial projection, a pawl pivotally mounted on said radialprojection, movable means carried by said radial projection and attachedto said pawl operative in a first position to hold said pawl inoperative engagement with said ratchet gear and in a second position tohold said pawl out of engagement with said ratchet gear, means carriedby said shaft for turning said radial projection with said shaft, saidlast-mentioned means being operative when said handle is rotated in saidfirst direction to move said movable means to said first position d andoperative when said handle is moved in a'second opposite direction tomove said movable means to said second position, and means carried bysaid projection preventing rotation of said projection only in saidsecond direction, said spring acting to spin said drum in said seconddirection to unwind the spring therefrom when said handle is rotated insaid second direction to disengage said pawl from said ratchet gear.

4. A manually operable spring starter as defined by claim 3, furtherincluding an overrunning clutch attached to said drum for coupling saiddrum to the shaft to be rotated, said clutch comprising a clutch memberdrivable by said drum only in said second direction and adapted tooverrun said drum when the speed of the shaft to which it is connectedexceeds the speed of rotation of said drum.

5. Apparatus for imparting a rapidly accelerating rotative movement to ashaft comprising, a stationary casing, a spring coiled within saidcasing with the outer end of said spring attached to the wall of saidcasing, a first shaft extending into said casing through one endthereof, bearing means rotatably supporting said first shaft, a crankarm secured to the outer end of said first shaft for rotating said firstshaft, a second shaft rotatably surrounding said first shaft, means onsaid second shaft for acting on the inner end of said spring to windsaid spring upon said second shaft when said second shaft is rotated ina predetermined direction, means for turning said second shaft in saidpredetermined direction when said first shaft is rotated by said crankarm in a first direction, and means for rendering said last mentionedmeans inoperative when said first shaft is rotated by said crank arm ina second direction, whereby the spring wound upon said second shaft willrotate said second shaft in a direction opposite to said predetermineddirection to restore said spring to its normal position.

6. A starter for an internal combustion engine having a drive shaft withan exposed end, said starter comprising a housing mounted on said engineover and in alignment with said shaft end; a coil spring in said housingand connected thereto; coupling means connected to said spring andmounted in said housing for rotation in response to energy stored insaid spring; means connected to said housing for locking said couplingmeans against rotation; means including a handle mounted on said housingand communicating therethrough to said spring for storing energy in saidspring when said looking means is engaged; means for releasing saidlocking means when energy is stored in said spring toimpart rotation tosaid coupling means; and clutch means on said shaft end for engagingsaid shaft and said coupling means in driving relation only when saidlocking means is released and said engine is not running.

7. The starter defined in claim 6 further characterized by said couplingand clutch means constructed and arranged to provide a short path offree travel for said coupling means after said locking means is releasedand before said coupling means and clutch means actually become engagedin driving relation whereby said cou-.

pling means gains an increment of kinetic energy prior to final drivingengagement with said shaft.

8. A starter for an internal combustion engine having an exposedrotating shaft and air cooling means associated with said shaft fordrawing air through said engine around said shaft, said startercomprising; a housing, means for mounting said housing on said engineover said shaft end and spaced from said engine to permit free entranceof air around said shaft; spring means in said housing; ratchet and pawlmechanism operatively associated with' said shaft and connected theretofor coupling said spring means and said shaft end when said engine isnot running, said ratchet and pawl mechanism being held in disengagementby centrifugal force when said engine is running; means mounted on saidhousing for storing energy in said spring; and means mounted on saidhousing 'for releasing said stored energy in said spring, whereby therelease of energy stored in said spring is imparted to said shaft onlywhen said engineis not running.

3 7 References Cited in the file of this patent UNITED STATES PATENTS2,568,136 Weimer Sept. "18; 1951 5 2,804,173' De Millar Aug.27, 1957

